/Engine/Source/Editor/UnrealEd/Public/Kismet2/BlueprintEditorUtils.h
Just removes the timeline from the associated timelist in the Blueprint. Does not remove the node graph object representing the timeline itself.
static void RemoveTimeline ( [UBlueprint](API\Runtime\Engine\Engine\UBlueprint) * Blueprint, class [UTimelineTemplate](API\Runtime\Engine\Engine\UTimelineTemplate) * Timeline, bool bDontRecompile )